
# 2.4微积分

# 2.4.1. 导数和微分
import numpy as np
from matplotlib_inline import backend_inline
import torch

def f(x):
    return 3 * x ** 2 - 4 * x

def numerical_lim(f,x,h):
    return (f(x+h)-f(x))/h

h = 0.1
for i in range(5):
    print(f'h={h:.5f}, numerical limit={numerical_lim(f, 1, h):.5f}')
    h *= 0.1
# 输出：h=0.10000, numerical limit=2.30000
# h=0.01000, numerical limit=2.03000
# h=0.00100, numerical limit=2.00300
# h=0.00010, numerical limit=2.00030
# h=0.00001, numerical limit=2.00003


# 2.4.2. 偏导数

# 2.4.3. 梯度










